CADMIUM ACCUMULATION IN LITTORINA-LITTOREA, MYTILUS-EDULIS AND CARCINUS-MAENAS - THE INFLUENCE OF SALINITY AND CALCIUM-ION CONCENTRATIONS

Accumulation of waterborne cadmium in Littorina littorea, Mytilus edulis and Carcinus maenus (collected in 1988 and 1989 around the island of Funen, Denmark) was investigated in a matrix of salinities (10 to 30 parts per thousand) and calcium concentrations (2.9 to 8.9 mM Ca++). Cadmium accumulation rates in soft parts of L. littorina, soft parts and shells of M. edulis and whole bodies and exoskeletons of C. maenas decreased with increasing salinity. Changes in the calcium concentrations accounted for 72% of the 'salinity effect' on cadmium accumulation rates in L. littorina, whereas calcium concentrations had little or no effect on cadmium accumulation in M. edulis. Cadmium accumulation in the whole body of C. maenas was affected equally by calcium concentrations and total salinity, whereas accumulation in the exoskeleton was mainly affected by changes in total salinity. Individual variability in cadmium accumulation in the organs of C. maenas was greater than the variation attributable either to changes in ambient calcium concentrations or total salinity. An appreciable amount of the inter-individual variability in the cadmium accumulation in all three species was correlated with wet:dry weight ratios of the tissues and size of the organisms.